SIMBAD references

In this paper we reexamine historical references to the supernova event of A.D. 1054 with a view to establishing a sequence astronomical events that minimizes apparent conflicts between the various sources. We find that the explosion of the supernova is likely to have occurred weeks to months before the commonly accepted date of 1054 July 4. This view is strongly supported by a number of European references to events visible in the evening sky during the spring that are likely to be associated with the appearance of the supernova. We find that the best fit to the light curve based on Chinese observations and a maximum visible apparent magnitude for a supernova located at the distance to the Crab Nebula also confirms the earlier explosion date.